Hematopoietic progenitor cell liabilities and alarmins S100A8/A9-related inflammaging associate with frailty and predict poor cardiovascular outcomes in older adults

Phenotypes and functions of "aged" neutrophils in cardiovascular diseases

Neutrophils are important effector cells of innate immunity and undergo several phenotypic changes after release from the bone marrow. Neutrophils with a late life cycle phenotype are often referred to as "aged" neutrophils. These neutrophils undergo functional changes that accompany stimuli of inflammation, tissue senescence and injury, inducing their maturation and senescence in the circulation and locally in damaged tissues, forming a unique late-life neutrophil phenotype. "Aged" neutrophils, although attenuated in antibacterial capacity, are more active in aging and age-related diseases, exhibit high levels of mitochondrial ROS and mitochondrial DNA leakage, promote senescence of neighboring cells, and exacerbate cardiac and vascular tissue damage, including vascular inflammation, myocardial infarction, atherosclerosis, stroke, abdominal aortic aneurysm, and SARS-CoV-2 myocarditis. In this review, we outline the phenotypic changes of "aged" neutrophils characterized by CXCR4high/CD62Llow, investigate the mechanisms driving neutrophil aging and functional transformation, and analyze the damage caused by "aged" neutrophils to various types of heart and blood vessels. Tissue injury and senescence promote neutrophil infiltration and induce neutrophil aging both in the circulation and locally in damaged tissues, resulting in an "aged" neutrophil phenotype characterized by CXCR4high/CD62Llow. We also discuss the effects of certain agents, such as neutralizing mitochondrial ROS, scavenging IsoLGs, blocking VDAC oligomers and mPTP channel activity, activating Nrf2 activity, and inhibiting neutrophil PAD4 activity, to inhibit neutrophil NET formation and ameliorate age-associated cardiovascular disease, providing a new perspective for anti-aging therapy in cardiovascular disease.

Circulating haematopoietic stem cells and long-term outcomes of COVID-19

BACKGROUND AND AIMS

An acute depletion of circulating haematopoietic stem/progenitor cells (HSPCs) occurs during COVID-19, especially among patients with a poorer disease course. We herein examined whether HSPCs levels at hospital admission for COVID-19 predict 1-year mortality and the long-COVID syndrome.

MATERIALS AND METHODS

Patients hospitalized for COVID-19 in an infectious disease ward were consecutively enrolled. Circulating HSPC levels were assessed by flow cytometry as cells expressing CD34 and/or CD133. Follow-up was performed for 12 months after hospitalization through the review of electronic medical records and demographic local registers.

RESULTS

The study included 100 patients, 36 of whom reported symptoms of long-COVID and 20 died during follow-up. The reduction of 1-SD of HSPCs was associated with a 3- to 5-fold increase in the risk of 1-year mortality. Age, admission hyperglycaemia, C-reactive protein peak, liver enzymes, the need of high-flow oxygen and/or invasive ventilation were predictors of mortality at univariate analysis. Among pre-existing comorbidities, coronary heart disease and chronic kidney disease, but not diabetes, were associated with 1-year mortality. In multivariate analyses, HSPCs remained significantly associated with 1-year mortality independently of confounders. The development of pneumonia an in-hospital treatment with glucocorticoids and convalescent plasma were associated with long-COVID symptoms at follow-up. HSPCs, diabetes and other comorbidities were not predictors of long-COVID.

CONCLUSIONS

In a cohort of patients hospitalized for COVID-19, lower HSPC levels at the time of admission were independent predictors of 1-year mortality. However, COVID-19 severity, but not HSPC level, was significantly associated with the development of long-COVID symptoms.

Frailty and the Interactions between Skeletal Muscle, Bone, and Adipose Tissue-Impact on Cardiovascular Disease and Possible Therapeutic Measures

Frailty is a global health problem that impacts clinical practice. It is complex, having a physical and a cognitive component, and it is the result of many contributing factors. Frail patients have oxidative stress and elevated proinflammatory cytokines. Frailty impairs many systems and results in a reduced physiological reserve and increased vulnerability to stress. It is related to aging and to cardiovascular diseases (CVD). There are few studies on the genetic factors of frailty, but epigenetic clocks determine age and frailty. In contrast, there is genetic overlap of frailty with cardiovascular disease and its risk factors. Frailty is not yet considered a risk factor for CVD. It is accompanied by a loss and/or poor functioning of muscle mass, which depends on fiber protein content, resulting from the balance between protein breakdown and synthesis. Bone fragility is also implied, and there is a crosstalk between adipocytes, myocytes, and bone. The identification and assessment of frailty is difficult, without there being a standard instrument to identify or treat it. Measures to prevent its progression include exercises, as well as supplementing the diet with vitamin D and K, calcium, and testosterone. In conclusion, more research is needed to better understand frailty and to avoid complications in CVD.

Role of Endothelial Progenitor Cells in Frailty

Frailty is a clinical condition closely related to aging which is characterized by a multidimensional decline in biological reserves, a failure of physiological mechanisms and vulnerability to minor stressors. Chronic inflammation, the impairment of endothelial function, age-related endocrine system modifications and immunosenescence are important mechanisms in the pathophysiology of frailty. Endothelial progenitor cells (EPCs) are considered important contributors of the endothelium homeostasis and turn-over. In the elderly, EPCs are impaired in terms of function, number and survival. In addition, the modification of EPCs' level and function has been widely demonstrated in atherosclerosis, hypertension and diabetes mellitus, which are the most common age-related diseases. The purpose of this review is to illustrate the role of EPCs in frailty. Initially, we describe the endothelial dysfunction in frailty, the response of EPCs to the endothelial dysfunction associated with frailty and, finally, interventions which may restore the EPCs expression and function in frail people.

Small molecule-induced epigenomic reprogramming of APL blasts leading to antiviral-like response and c-MYC downregulation

Acute promyelocytic leukemia (APL) is an aggressive subtype of acute myeloid leukemia (AML) in which the PML/RARα fusion protein exerts oncogenic activities by recruiting repressive complexes to the promoter of specific target genes. Other epigenetic perturbations, as alterations of histone H3 lysine 9 trimethylation (H3K9me3), have been frequently found in AMLs and are associated with leukemogenesis and leukemia progression. Here, we characterized the epigenomic effects of maltonis, a novel maltol-derived molecule, in APL cells. We demonstrate that maltonis treatments induce a profound remodulation of the histone code, reducing global H3K9me3 signal and modulating other histone post-translational modifications. Transcriptomic and epigenomic analyses revealed that maltonis exposure induces changes of genes expression associated with a genomic redistribution of histone H3 lysine 4 trimethylation (H3K4me3) and lysine 27 acetylation (H3K27ac). Upregulation of interferon alpha and gamma response and downregulation of c-MYC target genes, in function of c-MYC reduced expression (monitored in all the hematopoietic neoplasms tested), represent the most significant modulated pathways. These data demonstrate the ability of maltonis to epigenetically reprogram the gene expression profile of APL cells, inducing an intriguing antiviral-like response, concomitantly with the downregulation of c-MYC-related pathways, thus making it an attractive candidate for antileukemic therapy.

Hematopoietic progenitor cell liabilities and alarmins S100A8/A9-related inflammaging associate with frailty and predict poor cardiovascular outcomes in older adults

Frailty affects the physical, cognitive, and social domains exposing older adults to an increased risk of cardiovascular disease and death. The mechanisms linking frailty and cardiovascular outcomes are mostly unknown. Here, we studied the association of abundance (flow cytometry) and gene expression profile (RNAseq) of stem/progenitor cells (HSPCs) and molecular markers of inflammaging (ELISA) with the cardiorespiratory phenotype and prospective adverse events of individuals classified according to levels of frailty. Two cohorts of older adults were enrolled in the study. In a cohort of pre-frail 35 individuals (average age: 75 years), a physical frailty score above the median identified subjects with initial alterations in cardiorespiratory function. RNA sequencing revealed S100A8/A9 upregulation in HSPCs from the bone marrow (>10-fold) and peripheral blood (>200-fold) of individuals with greater physical frailty. Moreover higher frailty was associated with increased alarmins S100A8/A9 and inflammatory cytokines in peripheral blood. We then studied a cohort of 104 more frail individuals (average age: 81 years) with multidomain health deficits. Reduced levels of circulating HSPCs and increased S100A8/A9 concentrations were independently associated with the frailty index. Remarkably, low HSPCs and high S100A8/A9 simultaneously predicted major adverse cardiovascular events at 1-year follow-up after adjustment for age and frailty index. In conclusion, inflammaging characterized by alarmin and pro-inflammatory cytokines in pre-frail individuals is mirrored by the pauperization of HSPCs in frail older people with comorbidities. S100A8/A9 is upregulated within HSPCs, identifying a phenotype that associates with poor cardiovascular outcomes.